This invention relates to battery chargers, and more particularly to battery chargers having cyclic charging cycles.
The use of wireless communication systems is growing fixed location. This allows users to, for with users now numbering well into the millions. One of the popular wireless communications systems is the cellular telephone, having a mobile station (or handset) and a base station. Cellular telephones allow a user to talk over the telephone without having to remain in a example, move freely about the community while talking on the phone.
Devices such as a mobile telephones, cordless telephones, and pagers typically use rechargeable batteries as a source of electric power. To enhance the usability of the mobile device, manufacturers are continually attempting to increase the amount of time required before the battery needs to be recharged. It has been found that during battery charging, an ionic barrier may form at the insulator between the cathode and the anode of the battery. As this ionic barrier forms, the capacity of the batteries decreases. Thus, it is desirable to recharge batteries while minimizing the formation of the ionic barrier.
The present invention is a cyclic battery charger designed to reduce the formation of the ionic barrier. The battery charger applies a current to the battery for a first period of time. To reduce the ionic barrier, a discharge current is applied to the battery for a second period of time. The charging current and discharging current are applied cyclically to the battery during the entire charging period. The discharge current may be applied by the battery charger, or may be the result of the current drawn from the powered device. The discharge current may be a fraction of the charging current, and is applied to the battery for only a limited time during the charging cycle as compared to the charging current.